Modified acetals



Patented Aug. 14, 1945 UNITED STATES PATENT OFFICE MODIFIED ACETALSWilliam Franklin Gresham, Wilmington, Del., as-

signor to E. I. du Pont de Nemonrs 8: Company, Wilmington, Del., acorporation of Delaware No Drawing. Application December 24, 1941,

Serial No. 424.292

2 Claims. (Cl. 260-615) This invention relates to a process for theprep- (Butoxymethoxy) ethanol aration of organic high molecular weightpoly- ClHnOCH20 CH2hOH mer-like compounds and more particularly to theirpreparation from 1,3-dioxolane and acetais. 'gg g gg gggfgg fifig ig Itlikewise relates to the resulting products. 5

The present invention provides new reaction xym th xy) thanol productsobtainable from the reaction of 1,3- CIhO(CHz)zOCI-hO(CHz)zOH dioxoianewith other organic compounds. haqnethox tho ethanol Another object ofthe invention is to provide new g s gg compositions of matter from1,3-dioxolane or its substitution products and acetals. Yet another(Metmxymethoxy) Pmilmol object is to provide a process for theinteraction cmocmowm) of 1,3-dioxolane and its substitution products Bta. (methgxymethoxy) propanol with acetals in the presence of an acidictype catacmocmocmcm) cmol-r lyst. Another object is to provide reactionconditions and catalysts for such reactions, whereby g a f f )butmmvaluable products are obtainable. Other objects and advantages of theinvention will hereinafter the higher aldehyde acetals, appear. .0

Valuable products are obtained in accord with 0 on the invention byreacting 1,3-dioxolane, substituted 1,3-dioxolane, or reactants whichform m these compounds with aeetals which include, for example. theiormals:

Bio

BIO

and the higher formals in which R1 and R: are similar or dissimilaralkyl, aryl, aralkyl, cyclic or alicyclic groups and especially hydroxyalkyl substitutions such as: compounds having the structural formulaRCH(0(CH-.-) sOH) 2, in which a is a positive integer greater than 1,examples of which include:

(Methoxymethoxy) ethanol CHsOCHzO (CH2) H (Ethoxymethoxy) ethanolCsHsOCHsOiCI-Is) zOI-I (Propoxymethoxy) ethanol CsHqOCHaOiCHzlzOH inwhich Bi and R: are similar to the above and R: is a substituted orunsubstituted alkyl group which will give products similar to thosedescribed under the formals for acetaldehyde, propanal. butanal, andhigher symmetrical and unsymmetrical aldehyde acetals. Substitutedacetals may be used in lieu of or in conjunction with the acetals, suchas:

2,3-dimethoxypropane (CI-Is) 2C (OCHJ) 2 2,2-diethoxypropane (CHI) :0(00am) 1 z-methoxy-il-ethoxypropane (CH1) :C(OCH:) OCsHs Cyclohexanoneketals.

The products of the invention are of relatively high molecular weight,and have at least one 1,3- dioxolane (or substituted 1,3-dioxolane)residue and at least one residue of the metal with a minimum of at leastthree residues, for example, the products resulting from the reaction of1,3-dioxolane with methylal will contain at least one 1,3- dioxolaneresidue as CH:OCHCH:O and at least one methylal residue as-OCH2O, with aminimum of three residues. two of which are similet. The compounds ofthe invention. many of which are polymeric in nature, are believed to beprimarily linear in form, although the cyclic compounds may be present.

The acetals may be reacted in accord with the procedural details morefully particuiarized hereinaitcr, with 1,3-dioxolane and itssubstitution products. 1.3-dioxolane has the chemical formula withnumbering as shown:

4. a CHr-O /(2!H| -H|- s i and may be obtained by reacting formaldehydeor a formal with ethylene glycol. Products with substituents in the 2position can be readily obtained by reaction of ketones or otheraldehydes either aliphatic or aromatic with ethylene glycol. Thus, byway of example, many compounds are obtained which may be employed inaccord with th invention, such as 2-methyl-l,3-dioxolane,2-ethyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane,

2,2 -diethyl- 1,3-dloxolane, 2-phenyl-l,3-dioxolane, 2,2-methylphenyl-1,3-di0xolane,

4-ethyl-l,3-dioxolane, 4-propyl-L3-dioxolane,4,5-dimethyl-1,3-diox0lane.

In lieu of 1,3-dioxolane, reactants may be used which form 1,3-dioxolaneand in such reactions there would be present the acetal to be reactedtogether with, for example, formaldehyde and ethylene glycol, or otherreactants which will form 1,3- faf i g le compounds are obtainable bythe reaction of small amounts of 1,3-dioxolane or its derivatives withlarge amounts of the acetal, that is, in the order of 1-100 and thereverse is also true. The greater the amount of 1,3-dioxolane present,the greater becomes the viscosity of the compounds until solids areeventually produced,

while contrarywise, the greater the ratio of the acetal the less viscouswill be the resulting compound. There appears to be no limiting factorrestricting the proportion of reactants.

The reaction between the 1,3-dioxolane and the acetal is eifected attemperatures ranging between -80 and 300 and preferably between 0 and150 C. Atmospheric, subor super-atmospheric pressures may be used and,ifthe last, pressure may range between 1 and 1000 atmospheres or higher.Normally excellent results are obtained at or about atmosphericpressure. If desired the temperature of the reaction, especially whencarried out at the boiling point of the reaction mixture, may becontrolled by varying the pressure on the boiling reactants.

It has been found advantageous to eflect the reaction in the presence ofan acidic type catalyst, such, for example, as sulfuric acid, phosphoricacid; the halogen acids, such as hydrochloric acid, hydrofluoric acid(alone or with BFII) boron fluoride (including its complexes with water,acids, esters, alcohols, and the like), para-toluene sulfonic acid,camphor sulfonic acid, and other acid catalysts of this general nature,Friedel-Crafts type catalysts other than BF: may be used, such as AlCh,AlBra, FeCla, and so forth, as well as inorganic acids generally andtheir salts such as sodium acid sulfate, sodium acid phosphate, and soforth.

The catalyst may be supported or not on inert supports such as charcoal,silica gel (which alone is a catalyst for the reaction), kieselguhr, andso forth. Concentrations of BBB, H2804 and similarly strong catalystsmay be extremely low; less than 0.1 and amounts down to as low as 0.001%of the strong acid catalyst have been found sumcient to give highmolecular weight products although high concentrations of the catalysteven equal to or greater than the weight of the dioxolane are likewisesatisfactory.

The reaction is preferably continued approximately to equilibrium inorder to obtain the above defined organic compounds. The reaction maythen be stopped by destroying the catalyst. This 'may be done byremoving it (in the case of silica gel, kieselguhr, and the like) or bytreating the reaction mixture with an inorganic base, such as ammonia,alkali metal, and alkaline earth metal hydroxides, carbonates,alkoxides, and so forth or an organic base, such as pyridine,dimethylamine, and the like. These bases are added in suflicient amountsto neutralize the catalyst when acid catalysts are used, and theunconverted reactants may be removed by distillation under reducedpressures. As soon as the catalyst has been neutralized, the reactionceases. The neutralized catalyst may be filtered off and the reactionmixture which remains treated for the recovery of the high molecularweight compounds.

In the reaction of the dioxolanes with the acetals and more especiallywhen the higher molecular weight products are being prepared thereusually will be found in the reaction mixture along with the highmolecular weight compound unreacted dioxoiane and the acetal togetherwith by-products and polymers which it is not desired to produce. It ispossible to inhibit the formation of the undesired products by carryingout the process in an intermittent or continuous manner whereby thedesired product is withdrawn from the reaction zone and the undesirableproducts, after being separated therefrom, are returned to the reactionzone. By this means it is possible to obtain high yields of the desiredproduct.

In addition to being instrumental in stopping the reaction at thedesired point, the neutralization of the catalyst tends to stabilize theproducts. It follows, therefore, that for high temperature uses no acidshould be present in the products. They should preferably be neutral oron the alkaline side.

Examples will now be given illustrating embodiments of the invention butit will be understood that it will not be limited by the detailsthereof. Parts are by weight unless otherwise indicated.

Example 1.A reaction mixture consisting of 222 parts of 1,3-dioxolane,684 parts of methylal and 4.5 parts of sulfuric acid was heated under areturn condenser supplied with a calcilum chloride drying tube for 6.5hours. Subsequent to neutralization of the catalyst by addition of 4.04parts of sodium hydroxide dissolved in 10 parts aseas'n of water to thecooled reaction mixture, the product was tractionally distilled, in theflnal stages under reduced pressure. 64.5 parts of di-(methoxymethoxy)ethane (CHsOCHaOCHsCHsOCHsOCHs) B. P. 03' (1/29 mm., was obtained.Physical and chemical constants of this compound are: bydroxyl No. 0.0,N 1.4014, density at 25 C. 1.0015.

Example 2.Under conditions described in Example l, 602 parts ofdl(p-chloroethyl) formal, 258 parts of 1,3-dioxolane and 4 parts ofsulfuric acid gave 105 parts or dKp-chloroethyoxymethoxy) ethane(ClOHzCHzOCI-hOCHaCHaOCI-IaOCHsCHrCl) paclty; as extractants forvegetable and animal oils; as ingredients in paint and varnish removers;as solvents in pigment drying; as softening agents in cork processingand as carbon removers to:- use in internal combustion engines.

I claim:

1. A process for the preparation of di(methoxymethoxy) ethane whichcomprises refluxing a reaction mixture of approximately the followingcomposition: 222 parts of 1,3-dioxolane, 684 parts of methylal, and 4.5parts of sulfuric acid for approximately 6% hours, neutralizing thecatalyst by the addition oi approximately 4.04 parts of sodiumhydroxide, dissolving in 10 parts of water and recovering thedi(methoxymethoxy) ethane from the reaction product by distillation.

2. A process for the preparation of di(methoxymethoxy) ethane whichcomprises refluxing a mixture of 1,3-dioxolane and methylal, the mixturecontaining a molar excess of methylal, in the presence of an acidiccatalyst until appreciable amounts of dlimethoxymethoxy) ethane areobtained, neutralizing the catalyst by the addition of an inorganic baseand recovering the di- (methoxymethoxy) ethane from the reaction mixtureby distillation.

WILLIAM FRANKLIN GRESHAM.

CERTIFICATE OF CORRECTION.

Patent No. 2,382,87 i.

August 9 L5- WILLIAM FRANKLIN GRESHAM.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,sec- 0nd column, line in, for "-cH ocH--cH o-", read -CH OCH -CH O-; d t

the said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of December, A. D. 19145.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.

aseas'n of water to the cooled reaction mixture, the product wastractionally distilled, in the flnal stages under reduced pressure. 64.5parts of di-(methoxymethoxy) ethane (CHsOCHaOCHsCHsOCHsOCHs) B. P. 03'(1/29 mm., was obtained. Physical and chemical constants of thiscompound are: bydroxyl No. 0.0, N 1.4014, density at 25 C. 1.0015.

Example 2.Under conditions described in Example l, 602 parts ofdl(p-chloroethyl) formal, 258 parts of 1,3-dioxolane and 4 parts ofsulfuric acid gave 105 parts or dKp-chloroethyoxymethoxy) ethane(ClOHzCHzOCI-hOCHaCHaOCI-IaOCHsCHrCl) paclty; as extractants forvegetable and animal oils; as ingredients in paint and varnish removers;as solvents in pigment drying; as softening agents in cork processingand as carbon removers to:- use in internal combustion engines.

I claim:

1. A process for the preparation of di(methoxymethoxy) ethane whichcomprises refluxing a reaction mixture of approximately the followingcomposition: 222 parts of 1,3-dioxolane, 684 parts of methylal, and 4.5parts of sulfuric acid for approximately 6% hours, neutralizing thecatalyst by the addition oi approximately 4.04 parts of sodiumhydroxide, dissolving in 10 parts of water and recovering thedi(methoxymethoxy) ethane from the reaction product by distillation.

2. A process for the preparation of di(methoxymethoxy) ethane whichcomprises refluxing a mixture of 1,3-dioxolane and methylal, the mixturecontaining a molar excess of methylal, in the presence of an acidiccatalyst until appreciable amounts of dlimethoxymethoxy) ethane areobtained, neutralizing the catalyst by the addition of an inorganic baseand recovering the di- (methoxymethoxy) ethane from the reaction mixtureby distillation.

WILLIAM FRANKLIN GRESHAM.

CERTIFICATE OF CORRECTION.

Patent No. 2,382,87 i.

August 9 L5- WILLIAM FRANKLIN GRESHAM.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,sec- 0nd column, line in, for "-cH ocH--cH o-", read -CH OCH -CH O-; d t

the said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of December, A. D. 19145.

(Seal) Leslie Frazer First Assistant Commissioner of Patents.

